aerial camera

a mechanical optical instrument with automatic and electronic elements; it is designed for obtaining aerial photographs of the earth’s surface from an airplane or other type of aircraft. The specific conditions in which this photographing must be accomplished—great distance from the objects to be photographed, rapid movement, and vibration during exposure—present special requirements for the aerial camera; it differs from ordinary cameras in having the following features: fully automatic operation, shock absorbing support frame, large picture format, and rapid frame advance. The world’s first aerial camera for march route and area photography from an airplane was invented by the Russian army engineer V. F. Potte during World War I (1914–18).

A distinction is made between aerial cameras designed for topographical work and those designed for reconnaissance work. The former presents more rigid requirements in order to guarantee high quality photographs for accurate measurement and description. Aerial cameras may have one or more lenses for plan views, perspectives, and panoramic surveys. Basic features of aerial cameras are their focal length, negative size, and minimum exposure time, which is as short as 1/1000 sec in Soviet aerial cameras.

Standard Soviet aerial cameras designed for topographical surveys, which have an 18 x 18 cm negative size, have focal lengths from 50 to 500 mm (70,100,140, and 200 mm are most commonly used) and corresponding field-of-view angles from 150° to 30°. Aerial cameras of either type are used for black and white or color aerial photographic surveying.

Aerial cameras with varying focal lengths, beginning with 88 mm, are also used abroad. With the most popular 23 x 23 cm negative size, this corresponds to field-of-view angles up to 125°.